Improvement in propellers



UNITED STATES HENRY \V. HEVITT,

llVlPROVEMENT OF NEV YORK, N. Y.

IN PROPELLERS.

Specification forming part of Letters Patent No. 9,763, dated June 7, 1853.

T0 all whom it may concern:

Be it known that I, HENRY '\V. llEWITT, of the city, county, and State of New York, have invented certain Improvements in Propellers for Propelling Steamboats and other Vessels, ot which, the following is a full, clear, and exact description,reference being had to the accompanying drawings, making part of this specification, inl which- Figure l is a plan; Fig. 2, a side elevation, and Fig. 3 a longitudinal vertical section taken at the line A (t of Fig. l; and Fig. at, a like section of the second part of my invention.

The same letters indicate like parts in all the figures.

The nature of my invention consists in giving to the paddles in their circuit a greater longitudinal than vertical motion imparted by a crank motion modified by the vibratory motion of a beam or beams, which vibratory motion of the beam is derived from the crank motion, so that the motion of the paddles shall be generated by the combined motion of the crank and the beam, the beam increasing the motion of the paddles in the direction of the propelling action beyond the diameter of the circle generated by the crank, while the motion toward and from the water is received directly from the crank or cranks 3 and my invention also consists in making the vibrating beam, in the combination above specied, to slide on its fulcrum, by reason of which combination the paddles begin to move back in the direction of the propelling action before the cranks in their descent reach the horizontal line in carrying the paddles down toward the water, and continue this motion in the direction of the propelling action until after the cranks in rising have passed the horizontal line or dead-poi nt, thus avoiding what is called backwater.

In the accompanying drawings. a a represent two parallel shafts,each with three cranks I) Z) l?, dividing the circle into three equal parts. These shafts run in suitable boxes secured to the boat and to the guards, in the same manner as the paddle-wheel shafts of steamboats, and the driving-power can be applied to one or both shafts in any suitable manner.

There are three bars c c c, which connect the corresponding cranks on the two shafts. The manner of forming the connections between the bars and the cranks, as also all the other connections, I do not deem necessary to describe, as every competent mechanical or steam engineer will know how to make such connections. The bars are made ofthe same size from end to end-that is, between the cranks-and to each is adapted a carriage d, which slides thereon freely but accurately, and with the bottom of each carriage is properly secured a frame e, which carries a series of paddles f, arranged at equal distances apart. The number' can be varied at pleasure from one upward.

If the carriage carrying the paddles were fixed on the bar c, it follows, as a necessary consequence, that any point on any one paddle would generate a perfect circle equal to the circle of the cranks and all the paddles alike, which would 'present little or no advantage over the motion of the paddles of the ordinary paddle-wheel, for the forward niotion of the boat through the water being equal, minus the slip, to the motion of any one paddle when perpendicularly under the shaft, and the horizontal motion ot' the paddles in entering and leaving the water being much less, by reason of their position at the time in the circle of motion, it follows that they must actually be pushed through the water by the motion of the boat, thus causing backwater, which would be the source of great loss of power, as in the common paddlewheel.

The difficulty above stated is avoided by giving to the paddles a longitudinal motion in addition to what is imparted to them directly by thecranks.

Each carriage is provided with two studs g g, one on each side; and the carriage is embraced by the lower end of a beam 7L, which is made double at the lower end for that purpose, and the two parts at this end are slotted longitudinally, as at i, to embrace the studs g, so as to slide thereon freely. The upper end of the beam is attached to a cross-head j, the ends of which slide between ways L 7.: in eallows-frames l l erected above the guards,

its length is connected with and turns on trunnions attached to an arch-piece m, extending over the carriage and bar c and con* nected with the ends thereof.

On inspection of the drawings it will be seen that the middle part of the vibrating and the said beam at or about the middle of beam, or vthe part jointed to the arch-piece m, must move in a circle equal to the circle of the cranks, and consequently the lower extremity will have a greater range of motion, say double, and this is connected with the carriage which can receive no other than a longitudinal motion from the beam by reason of sliding on the bar and in the slots in the lower end of the beam, it follows that while the paddles are carried directly bythe cranks in a circle equal to their own circle the beam imparts to them an additionl longitudinal motion, so that the curve of their circuit is generated by the motion of the cranks and the vibration of the beam, thus generating acurve represented by the red line in Fig. 3, and thus greatly increasing the longitudinal relatively to the vertical motion and in a great measure avoiding the loss produced by backwater.

In the arrangement so far as explained the paddles Aonly begin to move back in the direction of the propelling action after the cranks have passed the dead-points and begin to vdescend below the horizontal line pass ing through their axis, so that in case of deep immersion they would still make backwater. This can be avoided by combining with the above an additional element, which has been specified as constituting in this combination the second part of my invention, and this additional combination is represented in Fig. 4,.Where all the parts and combinations, so far as described, Will be found; but instead of having the vibrating beam provided with a cross-head it is made with a longitudinal slot n, adapted to slidevon a rod o, attached to the gallows-frame, the said rod constituting a fnlcrum, so that the beam slides on its fulcrum, the lever alternately increasing and decreasing the length. The effect of this combination is to cause the paddles to begin their back movement in the direction of the propelling action before the cranks reach the horizontal line passing through their axis as they descend, and continue this motion 'after the cranks have risen above the horizontal line, and from the time thc cranks descend to until they reach the horizontal line in ascending the paddles move in the direction of the propelling action nearly equal distances at equal periods of time, as represented by the dotted line, which represents the curve which would be generated by a point on any one paddle.

Having thus described the principle or character of my invention which distinguishes it from all other things before known and the mode of construction which I have adopted,

`I Wish it to bc understood that I do not limit myself to the mode of construction specified, as other modes of construction may be devised operating on the same principle and giving the same action to the paddles by equivalent means. c

What I claim as my invention, and desire to secure by Letters Patent, is-

I. Giving to the paddles in their circuit a greater longitudinal than vertical motion imparted by a crank motion, substantially as specified, in combination with the vibratory motion of a beam or beams derived from the same crank motion, substantially as and for the purpose specified. Y

2. In the combination above specified, making the beam or beams slide on the fulorum or fulcra, substantially as specified, by means of which additional element in the combination I am enabled to impart to the paddle or paddles the back motion in the direction of the propelling action during more than the lower halt' of the crank motion, substantially as specified, and for the purpose set forth.

II. W. HEWITT. Witnesses:

CHs. M. KELLER, CHAs. M. BAMBURGH. 

